Although solenoid-actuated valves are well suited for automatic remote control, because of the limited power developable by a conventional solenoid, such valves generally are limited in use to installations in which the solenoid actuation is opposed by low forces. Consequently, where the opposing forces are high, as in opening a lift valve against a considerable hydraulic head and a spring sufficiently strong to hold the valve normally closed, a solenoid-actuated valve is impractical except as a pilot valve, and some other means must be resorted to for directly actuating the lift valve. The problem posed by the shortcoming, powerwise, of solenoid-actuation is particularly apparent in attempting to render fool-proof the dumping of the usual plain water coolant from the cooling system of a diesel locomotive when the latter has to be shut down for repairs under freezing conditions and, as usual, the available expedient is a manually operated dump valve. It is with the adaptation of a solenoid-actuated valve for such heavy duty use that the present invention is particularly concerned.